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Re: BCAL timing for a mip
Excellent point Elton - I forgot about that single cell detail -
a very important one.
Thank you
Alex
At 10:45 AM -0500 2/26/08, Elton Smith wrote:
>HI Alex,
>
>Just a note on your comment (1) Stefano said that KLOE achieved 320 ps
>for mips.
>
>My understanding of his statement (as well as in discussions following) is
>that the 320 ps was for a single 4x4 cm2 cell measurement (very close to
>our segmentation in the beam test). Their resolution for a mip would be
>~320/sqrt(6)=130 ps for 6 radial readout segments. This number is
>consistent with the statistical term in their timing resolution (assuming
>200 MeV of equivalent energy for a muon) of sigma~56/sqrt(E) =
>56/sqrt(0.2) = 125 ps.
>
>Looking back at the notes on cosmic ray timing (e.g. GlueX-doc836 and
>summary GlueX-doc-842), I see that the time resolution quoted from our
>cosmic-ray tests (see GlueX-doc-842, p 27) of sigma_cell~426 ps is also
>for a single cell. Therefore, to estimate the resolution for a mip, one
>should also divide by sqrt(6), namely sigma_mip ~ 426/sqrt(6) = 173 ps.
>
>So these two results are not too different, but both need to be
>extrapolated to the expectation for a particle traversing the entire bcal
>module as a measure of the estimated resolution for a mip.
>
>Cheers, Elton.
>
>Elton Smith
>Jefferson Lab MS 12H5
>12000 Jefferson Ave
>Suite # 16
>Newport News, VA 23606
>elton@jlab.org
>(757) 269-7625
>(757) 269-6331 fax
>
>On Tue, 26 Feb 2008, Alex Dzierba wrote:
>
>> Hi All
>>
>> At Friday's phone conference we are meant to be having a discussion
>> of timing for charged particles from BCAL. Since some work has been
>> done with cosmic rays - can someone take responsibility for coming up
>> with a number for BCAL? As far as I know, the current estimate is
>> of order 420 ps based on Christine's cosmics analysis and a followup e-mail
>> exchange between Christine and Elton. Andrei - have you done any
>> independent analysis with cosmics? Maybe a two-page note summarizing
>> what we know and how we know it would be appropriate.
>>
>> I am currently working on the analysis of the fiber emission spectra
>> I received from Blake last night. After that I will produce 2-3 slides
>> showing how 420 ps allows to separate pi/proton but not pi/K
>> for the reactions of interest.
>>
>> Two other comments: (1) Stefano said that KLOE achieved 320 ps for
>> mips and (2) Zisis is doing work on understanding BCAL response to
>> protons (apart from timing).
>>
>> Cheers
>> Alex
>> --
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Alex R. Dzierba
>> Chancellor's Professor of Physics (Emeritus)
>> Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
>> JLab Visiting Fellow
>> Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
>> Home Phone: 812-825-4063 Cell: 812-327-1881 Fax: 866-541-1263
>> http://www.dzre.com/alex
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alex R. Dzierba
Chancellor's Professor of Physics (Emeritus)
Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
JLab Visiting Fellow
Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
Home Phone: 812-825-4063 Cell: 812-327-1881 Fax: 866-541-1263
http://www.dzre.com/alex
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~